From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 38098C54E5D for ; Mon, 18 Mar 2024 13:08:21 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9680E10E1D2; Mon, 18 Mar 2024 13:08:20 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=collabora.com header.i=@collabora.com header.b="vGRozkTj"; dkim-atps=neutral Received: from madrid.collaboradmins.com (madrid.collaboradmins.com [46.235.227.194]) by gabe.freedesktop.org (Postfix) with ESMTPS id 9CA1B10E1D2 for ; Mon, 18 Mar 2024 13:08:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1710767297; bh=SnAKMgM1EBF6N1x++NISuDhonukjQwL7rTEfMeIow+0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=vGRozkTj2rkGNWeh+anT1OPdoCbCItKqnVxt6JyGe3gZDl+cbiN2gp3EpBHpG7tZI xEPfL2C9UHv/DRgJBXzXHxvU2Lomv80EZUtu9h7qussKYXQ4XWdI+X7OCcHVNSmq3o oVoxUCWvK4L71sZ01y/sFn0Q8+0MoUV/Ca5bLmhBCvuZufGCK1sf0nxSClL8vA3va7 rUYBXETeVWEx+xJ1zQiQJZEGZEaerwBIMZwciKxHFJ5aCtHS1HubARf5FhNqUY9UD/ 3hqwLRRa9vE3xFSUC2P6gxTwTgu4KS708P2PVtu3PYIEBeQ0LRQV8+bc3cE6MrCwQQ G6MzJ8HLYcl/w== Received: from localhost (cola.collaboradmins.com [195.201.22.229]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) (Authenticated sender: bbrezillon) by madrid.collaboradmins.com (Postfix) with ESMTPSA id EDB083780A0B; Mon, 18 Mar 2024 13:08:16 +0000 (UTC) Date: Mon, 18 Mar 2024 14:08:15 +0100 From: Boris Brezillon To: Steven Price Cc: Liviu Dudau , dri-devel@lists.freedesktop.org, Robin Murphy , kernel@collabora.com, kernel test robot Subject: Re: [PATCH] drm/panthor: Fix the CONFIG_PM=n case Message-ID: <20240318140815.44de8110@collabora.com> In-Reply-To: <2af13565-f3d7-47c3-8083-da86669a34e1@arm.com> References: <20240318085855.994179-1-boris.brezillon@collabora.com> <2af13565-f3d7-47c3-8083-da86669a34e1@arm.com> Organization: Collabora X-Mailer: Claws Mail 4.2.0 (GTK 3.24.38; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On Mon, 18 Mar 2024 11:31:05 +0000 Steven Price wrote: > On 18/03/2024 08:58, Boris Brezillon wrote: > > Putting a hard dependency on CONFIG_PM is not possible because of a > > circular dependency issue, and it's actually not desirable either. In > > order to support this use case, we forcibly resume at init time, and > > suspend at unplug time. > > > > Reported-by: kernel test robot > > Closes: https://lore.kernel.org/oe-kbuild-all/202403031944.EOimQ8WK-lkp@intel.com/ > > Signed-off-by: Boris Brezillon > > Reviewed-by: Steven Price > > > --- > > Tested by faking CONFIG_PM=n in the driver (basically commenting > > all pm_runtime calls, and making the panthor_device_suspend/resume() > > calls unconditional in the panthor_device_unplug/init() path) since > > CONFIG_ARCH_ROCKCHIP selects CONFIG_PM. Seems to work fine, but I > > can't be 100% sure this will work correctly on a platform that has > > CONFIG_PM=n. > > The same - I can't test this properly :( > > Note that the other option (which AFAICT doesn't cause any problems) is > to "select PM" rather than depend on it - AIUI the 'select' dependency > is considered in the opposite direction by kconfig so won't cause the > dependency loop. Doesn't seem to work with COMPILE_TEST though? I mean, we need something like depends on ARM || ARM64 || (COMPILE_TEST && PM) ... select PM but kconfig doesn't like that drivers/gpu/drm/panthor/Kconfig:3:error: recursive dependency detected! drivers/gpu/drm/panthor/Kconfig:3: symbol DRM_PANTHOR depends on PM kernel/power/Kconfig:183: symbol PM is selected by DRM_PANTHOR which id why I initially when for a depends on PM > Of course if there is actually anyone who has a > platform which can be built !CONFIG_PM then that won't help. But the > inability of anyone to actually properly test this configuration does > worry me a little. Well, as long as it doesn't regress the PM behavior, I think I'm happy to take the risk. Worst case scenario, someone complains that this is not working properly when they do the !PM bringup :-).